新型混合级联多电平换流器调制策略  

New Modulation Strategies for Hybrid Cascaded Multilevel Converter

作　　者：薛英林[1] 徐政[1] 唐庚[1] 郑翔[2] 刘正富[1] 

机构地区：[1]浙江大学电气工程学院,浙江省杭州市310027 [2]浙江电力调度通信中心,浙江省杭州市310007

出　　处：《电力系统自动化》2012年第22期108-114,共7页Automation of Electric Power Systems

基　　金：国家高技术研究发展计划(863计划)资助项目(2012AA050205)~~

摘　　要：重点研究了不同运行模式下混合级联多电平换流器的调制策略。首先,为降低导通开关的开关频率和稳态损耗,提出了具有基频开关特性的不对称方波调制策略;分析了该调制方式下整形电路与外界系统的能量交换特性,并给出了电压调制比和占空比的取值范围。其次,提出了适于整形电路的改进载波移相调制方法和子模块电容电压均衡策略;研究了混合级联多电平换流器的直流闭锁模式和静止同步补偿器运行模式,指出通过修正调制参考波稳态调制策略,其仍可适用于静止同步补偿器运行模式。最后,PSCAD/EMTDC仿真结果验证了所述调制策略的有效性和可行性。Modulation strategies of the hybrid cascaded multilevel converter （HCMC） under different modes are studied. Firstly, to reduce switching frequency and losses of director switches, a novel asymmetrical square wave modulation at fundamental switching frequency is proposed. Under this modulation, the energy exchange characteristic between the wave shaping circuit and the outside system is analyzed, and then the range of the voltage modulation ratio and duty ratio under steady operation is derived. Secondly, a modified phase-shifted carrier-based pulse width modulation （PWM） with sub-module capacitor voltage balancing strategy is developed for the wave shaping circuits. Moreover, the direct current blocking mode and static synchronous compensator mode are also investigated, and it is pointed out that the modulation strategy under steady operation mode can be effective under the latter mode by amending the modulation reference voltage. At last, the effectiveness and feasibility of modulation strategies is verified by PSCAD/EMTDC simulation.

关 键 词：直流输电 多电平换流器 调制策略 能量平衡 直流闭锁 动态无功补偿 

分 类 号：TM46[电气工程—电器]